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_-----------O&.A------------
Bedllner 'Charts
and Gear Inspection
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Me-aslJre-s V'iinltionl in e.nter Distance MiUIJ:t1i' Rbtlltu)rllIl Motion.
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2.4 GEAR TECHNOLOGY
Robed E. Sm'ith
is the principal in R.E. Smilh &
Co., gear consultants of
Roehester; NY. and one of Gear
Technology's technical editors.
HI! ha oller 50 years of experitinct!
in gllaring and is Ihl! author
of numerous {JtIpersandanlcles.
He: is also very active in AGMA
standards development.
Question submitted by
Ramiro C. Salinas
Co.rpus Christi Army Depot
Corpus Christi, TX
Q:What are redliner charts.and who
still does redliner charts?
Answer submitted by:
Robert E. Smith
R.E. Smith & Co.
A: For marty years, the terms "red
liner" and "red line charts" have been
used by the Fellows Corporation in rela-
lion to the:ir line of double flallk com-
posite testers, For example, they made
Ille No.4 Fellows Fim~-Pllch Red Liner
and the No. 12RL Red Liner. Double
flank composite gear inspeetion is
shown chematically in Figure I. These
instruments were in such common use
thai. the term "red liner" became synonymous,
w.ith double flank composite
inspection,
The tenn "red line charts" apparently
came from the facl that early recorders
used pens that wrote with red ink. These
were a constant maintenance problem,
diue to dogging and spatter. Later
recorder u ed thermal writing pens and
paper, thermal array printers. or even
printer attached to PC computers.
Double flank composite testers are made
by many different. companies and can use
a variety of writing methods that do not
produce a "red line" on the chart.
To compound the confusion even
more, the 'term "compo ite' inspection
has been taken to mean double flank
composite inspection beeau e it was in
such common use. As can be een in
Figure I, there is another type of composite
inspect jon, called single flank
composite, tilat can be used. Today, both
type appear in gear quality standards
such as AGMA and ISO.
Double and single Hartle composite
testing results in charts such as thai
shown in Figure 2. However, they mean
completely different things, As Figure I
bows, double flank composite test
measure center distance variation as the
gears mil Ihrougb light mesh. Single
flank composite testing, however, mea-
sures rotational motion variation, as the
gears roll thrilugh mesh at standard cen-
ter distance. with backlash.
One can see that the continued use of
the term "red liine chart." is not a very
good idea. The terms "double flank com-
posite chart" or "single flank composite
chart" would be more accurate and prevem
confusion as to what the data mean .
The 0000